U.S. Pat. No. 4,351,077 to Hofmann, incorporated herein in its entirety by this reference, discloses an exemplary automatic swimming pool cleaner. Included as part of the cleaner is a body (called a “head”) incorporating a buoyancy chamber. As described in the Hofmann patent, the buoyancy chamber preferably is provided with a hollow float. This chamber ensures that while the head will sink with the aid of any necessary weights onto the surface to be cleaned it will, nevertheless, be correctly orientated thereto.
See Hofmann, col. 3, 11. 55-58 (numeral omitted). Such hollow float is not depicted in the Hofmann patent, however, nor is it otherwise detailed.
U.S. Pat. No. 5,014,352 to Kallenbach, also incorporated herein in its entirety by reference, discusses automatic swimming pool cleaners likewise including a main body through which a fluid-flow passage extends. According to the Kallenbach patent, “normally used floats . . . have been removed and replaced” in favor of a hollow hemispherical part “[p]rojecting rearwardly from the upper part of the body.” See Kallenbach, col. 2, 11. 59-60; col. 3, 11. 19-22. In commercial embodiments of the cleaners of the Kallenbach patent, the hemispherical part is opaque and the float thus not visible.
U.S. Pat. No. 5,882,512 to Denkewicz, Jr., et al., similarly incorporated herein in its entirety by reference, details additional automatic swimming pool cleaners which may filter water both mechanically and chemically. By contrast with the “suction-side” cleaners of the Hofmann and Kallenbach patent-which attach to the inlet side of a swimming pool water-circulating pump—various illustrated cleaners of the Denkewicz, Jr. patent connect to the outlet side of the pump. Such cleaners often are referred to as “pressure-side” cleaners and sometimes lack any sort of dedicated float.
None of these patents explicitly identifies the shape of any buoyancy-enhancing float for an automatic swimming pool cleaner. None, further, describes a float visible to persons purchasing and using automatic swimming pool cleaners. Although the innovative cleaners of the Denkewicz, Jr. patent perform functions beyond mechanically filtering water, neither they nor other conventional swimming pool cleaners provide any indication of the temperature of the water or other fluid in which the cleaners operate. Having water-temperature indicating ability in a cleaner frequently may be useful, both in determining whether the water in the vessel is suitable for swimming and, potentially, in ascertaining whether the cleaner is likely to operate acceptably (or optimally).